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Hypothermia

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~Hypothermia~
Classifications and external resources
ICD-10 T68
ICD-9 780.9, 991.6

Hypothermia refers to any condition in which the temperature of a body drops below the level required for normal metabolism and/or bodily function to take place. In warm-blooded animals, core body temperature is maintained at or near a constant level through biologic homeostasis. When the body is exposed to colder temperatures, however, its internal mechanisms may be unable to replenish the heat that is being lost to the body's surroundings.

Hypothermia is the opposite of Hyperthermia. Because the words sound alike, they are easily confused. Many people confuse Hypothermia and Pneumonia by name, yet they are two utterly different conditions.

Contents

[edit] Stages of Hypothermia in Humans

  • Stage 1 - Body temperature drops 1°C - 2°C below normal temperature C (1.8°-3.6°F, or between 99°F - 95°F), mild shivering occurs. Normal shivering can begin. Unable to perform complex tasks with the hands, shiver may be mild to severe and the hands become numb. Blood vessels in the outer extremities contract, lessening heat loss to the outside air. Breathing becomes quick and shallow. Goose bumps form, to raise body hair on end in an attempt to create an insulating layer of air around the body.
  • Stage 2 - Body temperature drops 2°C - 4°C (3.6°F - 7.2°F, or between 95°F - 90°F). Shivering becomes more violent. Muscle miscoordination becomes apparent. Movements are slow and labored accompanied by a stumbling pace and mild confusion, but the victim may appear alert. Surface blood vessels contract further as the body focuses its remaining resources on keeping the vital organs warm. Victim becomes pale. Lips, ears, fingers and toes may become blue.
  • Stage 3 - Body temperature drops below approximately 32.2°C (90°F) (normal is 37°C or 98.6°F). Violent shivering persists, difficulty speaking, sluggish thinking, amnesia starts to appear, unable to use hands, stumbling. Cellular metabolic processes shut down. Below 86°F (30°C) shivering stops and the exposed skin becomes blue and puffy, muscle coordination very poor, inability to walk, incoherent/irrational behavior to stupor, pulse and respiration rates much decreased. Major organs fail. Clinical death occurs.

Note - Because of decreased cellular activity in stage 3 hypothermia, the body will actually take longer to undergo brain death

  • Do not rub or massage the patient
  • Do not give alcohol
  • Do not give food or drink (this includes warm drinks, this is only in extreme cases. The reason being that blood is diverted from the major organs where it is needed, and is sent to the stomach and intestines to digest the food/liquid, therefore lowering the core temperature further.)
  • Do not allow the body to become vertical
  • Move the patient with care. If the patient is moved too much, fatal cardiac arrythmias such as V-fib could be triggered.

Any of these actions will divert blood from the critical internal organs and may make the situation worse.

What you should do...

  • Call the emergency services.
  • Get the patient to shelter.
  • If possible, put the patient in a bath with medium-temperature water, with the clothes on. Do not do this to an elderly patient as death may occur since blood flows to the surface of the skin restricting flow to the heart and brain.
  • Place hot water bottles (wrapped in a cotton sock) in the patient's armpits and between their legs
  • Monitor the patient and be prepared to give Cardio-pulmonary resuscitation.
  • Remove wet clothing if and only if a dry change is available.
  • If in a wilderness environment (such as camping) and other treatments are not possible, remove wet clothing from the victim and from one other person. Both individuals should get into the same sleeping bag if possible, or wrap in the same blanket, if the sleeping bag is too small.

If the hypothermia has become severe, notably if the patient is incoherent or unconscious, re-warming must be done by trained professionals. Bystanders should only remove the patient from the cold environment and call emergency services to get advanced medical care as quickly as possible.

Note
Moving a severely hypothermic person can—and most likely will—cause ventricular fibrillation (cardiac arrest). So, if possible, wait for trained emergency workers arrive. If help is over thirty minutes away, move the patient to an area that shelters them from the wind and cover or wrap them in a blanket.

[edit] Hospital Treatment

In a hospital, warming is accomplished by external techniques (blankets, warming devices) for mild hypothermia and by more invasive techniques such as warm intravenous fluids or even lavage (washing) of the bladder, stomach, chest and abdominal cavities with warmed fluids for severely hypothermic patients. These patients are at high risk for arrhythmias (irregular heartbeats), and care must be taken to minimize jostling and other disturbances until they have been sufficiently warmed, as these arrhythmias are very difficult to treat while the victim is still cold. An important tenet of treatment is that a person is not dead until they are warm and dead. Remarkable stories of recovery after prolonged cardiac arrest have been reported in patients with hypothermia. This is presumably because the low temperature prevents some of the cellular damage that occurs when blood flow and oxygen are lost for an extended period of time.

[edit] Prevention

In air, most heat is lost through the head [1], so hypothermia can be most effectively prevented by covering the head. Having appropriate clothing for the environment is another important prevention. Fluid-retaining materials like cotton can be a hypothermia risk; if the wearer gets sweaty on a cold day, then cools down, they will have sweat soaked clothing in the cold air. For outdoor exercise on a cold day, it is advisable to wear fabrics which can wick away sweat moisture. These include wool or synthetic fabrics designed specifically for rapid drying.

Heat is lost much more quickly in water. Children can die of hypothermia in as little as two hours in water as warm as 16°C (61°F), 289° K), typical of sea surface temperatures in temperate countries such as Great Britain. Many seaside safety information sources fail to quote survival times in water, and the consequent importance of diving suits, possibly because the original research into hypothermia mortality in water was carried out in wartime Germany on unwilling subjects. There is an ongoing debate as to the ethical basis of using the data thus acquired.

There is considerable evidence, however, that children that suffer near-drowning accidents in water near 0°C (32°F, 273°K) can be revived up to two hours after losing consciousness. The cold water also considerably lowers metabolism, allowing the brain to withstand a much longer period of hypoxia.

[edit] Medically Induced

See induced hypothermia

[edit] See also

[edit] References

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[edit] External links

de:Hypothermie es:Hipotermia fr:Hypothermie it:Ipotermia he:קור (תסמין למחלה) nl:Hypothermie ja:低体温症 pl:Hipotermia pt:Hipotermia fi:Hypotermia uk:Гіпотермія

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